• Journal of Biosystems Engineering
• /
• v.23 no.4
• /
• pp.365-372
• /
• 1998

This study was carried out to develop a nutrient-solution mixing-and-supplying system, which used a low-cost metering device instead of expensive metering pumps and a fuzzy logic controller. A low cost and precise overflow-type metering device was developed and evaluated by testing the flow discharge for the automatic nutrient-solution mixing-and-supplying system for snail-scale hydroponic sewers. The fuzzy logic controllers, which could predict and meet the desired values of EC and supply rate of nutrient solution were developed and verified by simulation and experiment. this fuzzy logic controller, whose algorithm consists of four crisp inputs, two crisp outputs and nine rules, was developed to predict the desired value of EC and supply rate of nutrient solution and two crisp inputs, one crisp output and nine rules used to control EC to the desired values. The nutrient-solution mixing-and-supplying system showed satisfactory EC control performance with the maximum overshooting of 0.035 mS/cm and the maximum settling time of 15 minutes in case of increasing 0.7 mS/cm. also, the accuracy of the overflow-type metering device in terms of the full-scale error was 2.29% when using solenoid valve only and 0.2% when using solenoid valve and flow control valve together.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.55 no.3
• /
• pp.51-62
• /
• 2013

The importance of environmental water has been risen in terms of river ecosystem soundness with preventing stream flow depletion in rural area, while enlarging agricultural reservoir project is conducted under the 4 main river restoration project for supplying more water to 4 main rivers. The aim of this study was to estimate the amount of environmental water release and analyze the release pattern during non-irrigation season in enlarged agricultural reservoirs. The 4 reservoirs (Dansan, Samga, Geumbong, Changpyeong) located on the upper region of Nakdong river were simulated applying the operation rule which was determined by release criteria curves. The simulated results indicated that the more environmental water could be released than the spillway release and continuous release was achieved with smaller range of fluctuation. In case of Changpyeong reservoir, average 506.0 thousand $m^3$ environmental water could be released on Feb., and it was about twice as much as the spillway release before the enlargement, and also, the 18 thousand $m^3$/day environmental water could be supplied to a stream consistently after enlargement. From the results, it was expected that the additional environmental water release will improve stream water flow during dry season in terms of quantity and quality of water.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.10
• /
• pp.1108-1120
• /
• 1990

The present study is to develop an intelligent control system for flexible manufacturing system, which is suitable for a variety of manufacturing types with smaller production rates. The controller is designed to integrate heuristic rules with optimization techniques for loading as well as flow rate of parts and ultimately meeting performance indices. The control function implemented by an optimization technique is to calculate short term production rates of parts. The heuristic control determined by production rules requires knowledge base to evaluate selected loading alternatives according to short term production rate and current process information, and also to determine final decision pertaining to loading. In this case, the knowledge base is constructed using the rules for evaluating alternatives, decision criteria, and flow control of parts in manufacturing system. The database is formulated by means of managing and updating current process information. A graphic system to monitor current status of the function and operation of manufacturing system is developed, and computer simulation is carried out to evaluate the performance of the proposed controller.

• Journal of the Korean Society for Library and Information Science
• /
• v.35 no.1
• /
• pp.47-75
• /
• 2001

The purpose of this study is to improve the academic information flow systems in university environment. The study explored various aspects of academic research flow systems, such as national standards and rules for digital library of electronic theses and dissertations, and national information infrastructure for digital data collection, management flow system through networks. Based on the analysis of current situations, the study developed the procedures and systems for digitalizing, collecting, processing, archiving, and providing of graduate research works.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.10a
• /
• pp.483-490
• /
• 2002

This paper presents the results of a comparative study between FEM and LEM on slope stability analysis. For validation, factors of safety were compared between FEM and LEM. The results from the two methods were in good agreement suggesting that the FEM with the shear strength reduction method can be effectively used on slope stability analyses. A series of analysis were then performed using the FEM for various constitutive laws, slope angles, flow rules, and the finite element discretizations. Among the findings, the finite element method in conjunction with the shear strength reduction method can provide reasonable results in terms of factor of safety. Also revealed is that the results of FEM can be significantly affected by the way in which the type of constitutive law and flow rule are selected.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.09a
• /
• pp.27-30
• /
• 2001

Flow and transport at fracture intersections, and their effects on network scale transport, are investigated in three-dimensional random fracture networks. Fracture intersection mixing rules complete mixing and streamline routing are defined in terms of fluxes normal to the intersection line between two fractures. By analyzing flow statistics and particle transfer probabilities distributed along fracture intersections, it is shown that for various network structures with power law size distributions of fractures, the choice of intersection mixing rule makes comparatively little difference in the overall simulated solute migration patterns. The occurrence and effects of local flows around an intersection (local flow cells) are emphasized. Transport simulations at fracture intersections indicate that local flow circulations can arise from variability within the hydraulic head distribution along intersections, and from the internal no flow condition along fracture boundaries. These local flow cells act as an effective mechanism to enhance the nondiffusive breakthrough tailing often observed in discrete fracture networks. It is shown that such non-Fickian (anomalous) solute transport can be accounted for by considering only advective transport, in the framework of a continuous time random walk model. To clarify the effect of forest environmental changes (forest type difference and clearcut) on water storage capacity in soil and stream flow, watershed had been investigated.

• Korean Journal of Child Studies
• /
• v.25 no.5
• /
• pp.95-110
• /
• 2004

This research employs the grounded theory approach among various qualitative methodologies in order to reach a deep understanding of both the experiential process that children undergo in block play and the essential meaning of it. The objects of this study are 22 children(female 7, male 15) in a 5-year-old class of K kindergarten at Guro district, Seoul. The result of this research shows that first, children take pleasure in block play because of the delight and sense of accomplishment in building, the joy in demolishing, and the happiness of embracing the world through dramatic play with building structures. Second, the characteristics of children's block play are popular subject of the play, decision of the subject, impromptu transformation and elaboration of building structures, and flow of the play according to friend/non-friend relationship. Third, the implicit rules shared by children have more significant influences upon the block play than the agreed rules at the beginning of semester.

• Journal of Information Technology Services
• /
• v.14 no.4
• /
• pp.45-60
• /
• 2015

Governments around the world invest in research and development (R&D) for different purposes : national economy, defence, environment, health, etc. as a means of national survival beyond the means of national competitiveness. These are usually programs with high social impact but low short-term economic impact or large scientific programs that are too expensive and risky for private sector investment alone. The Republic of Korea has also shown a very successful model of economic progress and social development through government R&D programs. However, there have been many corruption scandals behind it while selecting awardees for government R&D programs in Korea. So, the Republic of Korea focused on reforming appraisal system for government R&D and began preparation for "Clean Appraisal System" last year. In this study, first we analyzed the related appraisal tasks through the review of laws and administrative rules and typed appraisal tasks according to the flow of the actors and time. Thus securing the information infrastructure and finally we drew the conceptual model of the system according to an open appraisal tasks by introducing an element of the OECD on open government typed appraisal tasks.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.1
• /
• pp.97-103
• /
• 2009

The process design of forward Extrusion and Upsetting of Axi-symmetric part has been studied in this paper. During the cold forging product; auto transmission Solenoid Valve part, the defects such as folding and under-fill can be appeared by the improperly controlled metal flow. In this study, to reduce the folding and under-fill the design of experiments has been used to find out the significant design variables in the design of forging process. This paper deals with an Process Planning with which designer can determine operation sequences even after only a little experience in Process Planning of Multi-Former products by multi-stage former working. The approach is based on knowledge-based rules, and a process knowledge-base consisting of design rules is built. Based on the systematic procedure of process sequence design, the forming operation of cold forged auto transmission Solenoid Valve part is analyzed by the commercial Finite Element program, DEFORM/2D.

• MALSORI
• /
• no.56
• /
• pp.185-194
• /
• 2005

In this paper, we present POSSDM (POSTECH Situation-Based Dialogue Manager) for a spoken dialogue system using a new example and situation-based dialogue management technique for effective generation of appropriate system responses. Spoken dialogue system should generate cooperative responses to smoothly control dialogue flow with the users. We introduce a new dialogue management technique incorporating dialogue examples and situation-based rules for EPG (Electronic Program Guide) domain. For the system response inference, we automatically construct and index a dialogue example database from dialogue corpus, and the best dialogue example is retrieved for a proper system response with the query from a dialogue situation including a current user utterance, dialogue act, and discourse history. When dialogue corpus is not enough to cover the domain, we also apply manually constructed situation-based rules mainly for meta-level dialogue management.